Blue lateral correction system for color television tubes

ABSTRACT

Two oppositely directed electromagnets are mounted on a printed circuit plate around the neck of the television tube, one oriented directly towards the beam of the blue gun and the other one provided with a pole strap extending partway around the tube in both directions, surrounding the portion of the tube in which the beams of the other two guns are located. The direction of the field intersecting the beam of the blue gun is opposite to that of the field intersecting the beams of the red and green guns.

United States Patent 1191 Hanke et a1. Aug. 20, 1974 BLUE LATERAL CORRECTION SYSTEM 3,611,221 10/1971 lkeuchi 313/77 ux. 3,657,675 4/1972 Anthony et a1. 313/77 X FOR COLOR TELEVISION TUBES 3,717,788 2/1973 Rogers 335/212 X [75] Inventors: Peter Hanke, Sarstedt;

Hans-Joachim Ludcke, Nastatten; Heribert Martinetz; Rolf Ohlhorst, Primary E i H both of Hildesheim, of Germany Attorney, Agent, or Firm-William R. Woodward; 73 Assignee: Blaupunkt-Werke GmbH, Flynn & Fnshauf Hildesheim; Germany 221 Filed: Sept; 12, 1973 21 Appl. No.: 396,445 [57] ABSTRACT Two oppositely directed electromagnets are mounted I Foreign Appllcatlon Priority Data on a printed circuit plate around the neck of the tele- Sept. 13, 1972 Germany 2244797 vision tube, one oriented directly towards the beam of the blue gun and the other one provided with a pole [52] US. Cl. 335/210, 313/76 strap extending partway around the tube in both direc- [51] Int. Cl. 1101f 7/00 tions, surrounding the portion of the tube in which the [58] Field of Search 335/210,212, 213; beams of the other two guns are located. The direc- 317/101 C; 313/76, 77 tion of the field intersecting the beam of the blue gun is opposite to that of the field intersecting the beams [56] References Cited of the red and green guns.

UNITED STATES PATENTS 3,555,473 l/l97l Figlewicz et a1. 335/212 3 Claims, 1 Drawing Figure BLUE LATERAL CORRECTION SYSTEM FOR COLOR TELEVISION TUBES to shift the electron beams transversely to their beam direction towards their common point of intersection ,by separate deflecting devices arranged on the picture tube neck. For one of the electron beams, usually the beam producing the blue light, in addition to the deflection towards the common point of intersection, still another lateral deflection is necessary. This deflection is known as the correction of the blue lateral error of a color television tube. It is known as such, regardless of whether the correction is applied to the blue beam or to one of the others. To carry out this correction, still another separate deflection arrangement has been necessary. I

A known form of such a correction device is constructed with three electromagnets, with one 'of the three electromagnets oriented radially towards one of the electron guns, while two others, likewise radially oriented, are disposed around the circumference of the picture tube neck on the two sides of the first electromagnet spaced therefrom by equal angles of more than 120. In such an arrangement each core rod of the electromagnets is provided with a small coil and with a large coil. The smaller coils lie closer to the picture tube neck than the larger coils and serve for dynamic correction, whereas the larger coils are provided for static correction. By means of a suitable mounting the three electromagnets are held and positioned on the picture tube neck. This known arrangement of correction coils is expensive, because it requires three pairs of coils and the coils are interconnected by hand wiring. This arrangement, furthermore, has only limited utility for color television tubes of the 1 thin neck type, because mutual interaction on each other by the electromagnets is not preventable.

It is an object of the present invention to avoid these disadvantages and to provide a correction system that is applicable to all the color televisiontubes in use at the present time.

SUBJECT MATTER OF THE PRESENT INVENTION Briefly, a first and second electromagnet are disposed on the opposite sides of the picture tube, each oriented perpendicularly to the direction of the beam produced by one of the guns, which may be taken to be the one for the blue signal, and these electromagnets are connected to produce oppositely directedmagnetic fields extending inside the tube neck so as to deflect the electron beam of the blue gun in one direction and to deflect the beams of the other two guns in the opposite direction. The electromagnet farthest from the beam of the blue gun isprovided with a pole strap extending around a portion of the circumference of the picture tube neck where the beams of the red and green guns are located.

In a particularly effective embodiment of the invenv tion, the two electromagnets are mounted on a printed circuit plate perpendicular to the tube neck which passes through a hole in the center of the plate closely fitting the tube neck. The printed circuit plate serves as a carrier for the electromagnet and is also provided with connection paths and connection elements for them. The connection elements are preferably of the kind with which an edge contact connector is connectible.

The'invention will be described by way of example with reference to the accompanying drawing, which is a diagrammatic plan view of the printed circuit plate with the electromagnets mounted thereon.

First and second electromagnets 2 and 3 are mounted on the printed circuit plate 1. The electromagnets each consist of a core 4,5, a smaller coil 6,7 and a larger coil 8,9. The electromagnets 2,3 are oriented perpendicularly to a cut-out 10 in the printed circuit plate 1, and disposed so that the smaller coils 6,7 are nearer to the cut-out 10 than the larger coils 8,9. The cut-out 10 is a circular aperture closely fitting around the surface of the color television tube neck 11, on which the printed circuit plate is mounted to serve as the carrier for the electromagnets 2,3. The electromagnets 2,3 are so disposed on the printed circuit plate that the first electromagnet 2 is perpendicular to the beam direction of the blue gun 12, whereas the second electromagnet 3 is provided with a pole strap 13 that surrounds a portion of the picture tube neck within which the beams of the red gun l4 and the green gun 15 are. located. in the drawing the configuration of the field of the electromagnets 2 and 3 is schematically indicated by dashed lines.

The smaller coils 6,7 serve provide dynamic correction, and the larger coils 8,9 provide static correction of the covergence error. The extent of the circumferential width of the pole strap 13 influences the course of the lines of force of the field, and this width can easily be made such that when the field is modified by operation of the first electromagnet 2 deflecting the beam of the blue gun 12, no reaction on the deflection of the electron beams of the red and green guns l4 and 15 arises.

The printed circuit plate 1 is provided with connection paths l6 and 17 and connection elements 18 and 19 (for coils 8 and 9 and for coils 6 and 7, respectively) the connection elements 18 and 19 being, for example, contacts for gripping connections with a plug (not shown), so that hand wiring of the assembly is not necessary.

Although the invention has been described with respect to a particular embodiment, it will be understood that variations and modifications may be made within the inventive concept.

We claim:

l. A correction system for correcting the blue lateral error of a color television tube of the type having first,

second and third electron guns in a triangular approximately parallel arrangement in a picture tube neck, comprising: i V first and second electromagnets (2,3), not more than two of them inall, disposed on the outside of said picture tube neck (11) opposite each other and oriented perpendicularly to the direction of the beam produced by said first gun (12), said first electromagnet being the nearer to the beam produced by said first gun, said electromagnets being connected to produce oppositely directed magnetic fields extending inside said neck so as to deflect the electron beam proplate (1) serving as a carrier therefor an provided with an aperture (10) corresponding to the external diameter of said picture tube neck (11), and in which, further, said printed circuit plate (1) is provided with connection paths and connection elements for said electromagnets.

3. A correction system as defined in claim 2 in which said connection elements are such that edge contact connectors are connectible therewith. 

1. A correction system for correcting the blue lateral error of a color television tube of the type having first, second and third electron guns in a triangular approximately parallel arrangement in a picture tube neck, comprising: first and second electromagnets (2,3), not more than two of them in all, disposed on the outside of said picture tube neck (11) opposite each other and oriented perpendicularly to the direction of the beam produced by said first gun (12), said first electromagnet being the nearer to the beam produced by said first gun, said electromagnets being connected to produce oppositely directed magnetic fields extending inside said neck so as to deflect the electron beam produced by said first gun in one direction and to deflect the beams produced by the other two guns in the opposite direction, and being also provided with ferromagnetic cores; and a pole strap (13) provided on said second electromagnet (3) and extending around a poRtion of the circumference of said picture tube neck (11), inside which the beams produced by said second and third electron guns are located.
 2. A correction system as defined in claim 1 in which said electromagnets are mounted on a printed circuit plate (1) serving as a carrier therefor an provided with an aperture (10) corresponding to the external diameter of said picture tube neck (11), and in which, further, said printed circuit plate (1) is provided with connection paths and connection elements for said electromagnets.
 3. A correction system as defined in claim 2 in which said connection elements are such that edge contact connectors are connectible therewith. 